Loud-speaker unit



Dec; 25, 1928.

H. HELLER ET AL LOUD SPEAKER UNIT Filed Dec. 2, 1926 INVENTOR ,07 QW wWy ATTORNEY I Patented Dec, 25,1928.

{UNITED-(STATES PATENT OFFICE.

ntrco HELLER AND O. MITCHELL, OF MILWAUKEE, WISCONSIN, ASSIGNORSTO A. C.KOOTZ, OFMILWAUK EE, WISCONSIN.

LOUD-SPEAKER UNIT.

Application filed December 2, 1926. Serial No. 152,111.

This invention relates to improvements in loud speaker units.

through from the armature to the diaphragm.

It is a further object of the invention to provide a novel and improvedmeans for mounting the spool which carries the influencing coil betweenthe poles of the permanent magnet, the pole pieces being utilized tofacilitate-the quick assembly of the spool between the pole pieces andwithin the magnet.

In the drawings:

-, Figure 1 is 'a vertical axial section through the housing of a loudspeaker unit, showing in side elevation the mechanism embodying thisinvention.

Figure 2 is a plan view of the mechanism as it appears when the dust capis removed from the housing.

Figure 3 is an elevation of the mechanism as viewed from the right inFigure 1, the

, pole pieces.

Like parts are'identified by the same reference characters throughoutthe several views.

This is a companion to our application,

' Ser. No. 152,112, filed Dec. 2, 1926, in which we have disclosed andclaimed the particular diaphragm mounting shown in the accompanyingdrawings, wherein the two parts 5 and6 of the housing are held togetherby screws 7 to enga e clampingly an annular rubber cushion 10 having achannel in its inner periphery engaged about the mar 'n of diaphragm 11..T ie mechanism for actuating the diahragmis enclosed by a removable ca12 i rictionally en aged about the perip cry of diaphragm ousing member6 and secured thereto, if desired, by screws 13.

. The housing member 6 comprises a mountingplate uponwhich the entireoperating mechanism is assembled. Ithe as sem bly of the operatingmechanism is unitary in the sense that the permanent magnet 15 is theonly part which is actually connected with the mounting plate, all othermechanism being carried thereby.

In order to fix the position of the permanent magnet on the mountingplate, we have found it convenient to provide the mounting plate withintegral bosses 16,17, and 18. Magnet 15 is of the ordinary horseshoetype, and it is disposed with one of its legs fiat in contact with thenon-magnetic mounting plate 6. Bosses 17 and 18 are disposed upon eitherside of the legand approximately in contact therewith while the end ofthe magnet leg abuts the boss 16. Bosses 17 and 18 are of slightlylessheight than the thickness of the magnet leg which they embrace. Thismakes it possible to secure the magnet rigidly in place by spanning itwith a dielectric strap 19. Any nonmagnetic substance might convenientlybe used for this strap but for the fact that it is also desirable to usethe strap as a carrier for the binding posts 20. For this purpose thestrap is provided with forwardly extending arms at 21 in which thebinding posts are fixed.

Between the poles of the horseshoe magnet 15 are the pole pieces 25 andan influencing coil 26 with which an armature 27 is assembled.The-armature is connected by a link 28 with diaphragm 11. Thelocation ofthe magnet is such that it is necessary to provide a hole at 29 throughwhich link 28 passes in a direct line between the armature anddiaphragm.

The structure hereinafter to be described is such as to make it possiblefor the magnet to be fixed to the mounting plate 6 as the first step inassembling the loud speaker unit. The spool 26 upon which theinfluencing coil 30 is wound may conveniently be made of bakelite orother dielectric or non-magnetic material and is provided with holes forthe leads 31 which connect coil 30 to thebinding posts 20. The 'ends ofthe spool are preferably recessed at 32 and provided with shoulders at33 against which the pole pieces may abut to define their spacingaccurately with reference to the armature 27 which projects from the endtangular plate adapted to bedisposed in face contact with the innersurface of the magnetic pole. From opposite sides of the plate flanges35 depend in engagement with the spool 26, while from the other sides ofthe plate similar flanges 36 project upwardly or downwardly, as the casemay be, and en brace the pole in the magnet. Figure 4 shows one polepiece assembled with the spool, the flanges being engaged with the endsof the spool. and flanges 36 being adapted to embrace one pole of themagnet. The other pole piece 25 is illustrated in a position forapplication to the spool in like manner. It will be obvious that whenboth pole pieces are assembled on the spool it is possible to push theentire assembly over the boss 16 and between the poles of the magnet,where the assembly will preferably fit very closely and will betrictionally retained by a certain amount of spring or resiliency in themagnet.

In order to complete the device it is only necessary to connect the linkpin 28 from armature 27 through hole 29 to the diaphragm 11 and toconnect the leads 31 to the binding posts 20. The mechanism will now beconn pletely operative, since the thickness of tongues 33 accuratelydefinesthe spacing between the opposing flanges 35 of the two polepieces 25 and the armature 27 is accurately centered between the polepieces during the operation, whereby it is connected to link pin 28.

It will be obvious that this device lends itself to ready assembly anddisassembly and to accurate and economical manufacture. The objects ofthe invention are, therefore, satisfie We claim:

1. A device of the character described including a mounting plateprovided with bosses, a magnet having a leg disposed between saidbosses, and a strap spanning said leg from one boss to another andconnected with said bosses, said leg being confined between said plateand strap, whereby to secure said magnet to said plate.

2. In a device of the character described, the combination with amounting plate, of a magnet having a leg disposed in contact therewith,and a strap connecting said magnet leg with said plate and provided witharms carrying binding posts, said leg being confined between said plateand strap.

3. In a device of the character described, the combination with amounting plate provided with laterally spaced bosses and a third bossofiset from a point between said first mentioned bosses, of a magnethaving a leg disposed between said spaced bosses and abutting said thirdboss, and a tie strap extending across the leg of said magnet and fixedto said first mentioned bosses.

4. In a device of the character described, the combination w h amounting plate provided with laterally spaced bosses and a third bossoil'set from a point between said first mentioned bosses, of a magnet:having a leg disposed between said spaced bosses and abutting said thirdboss, and a tie strap extending across the leg of said magnet and fixedto said first mentioned bosses, said tie strap having forwardlyprojecting arms carrying binding posts, together with an iniluencingcoil associated with said magnet and provided with leads connected tosaid binding posts.

5. The combination with a housing, and a diaphragm operativcly mountedtherein. of a set of positioning bosses on a portion of said housing, amagnet having an apcrtured leg abutting said portion and confinedbetween said bosses, an armature within said magnet, and a linkextending through the aperture of the leg of said magnet from saidarmature to said diaphragm.

(3. The combination with a. diaphragm housing and a diaphragmoperativcly mounted therein, of a set of spaced bosses at the rear ofsaid housing. a horseshoe magnet having an apertured leg abutting saidhousing and confined lJllWQtll said bosses, a. dielectric strap memberspanning two of said bosses across the aperturcd leg of said magnet andfixed to said bosses, whereby to secure said magnet to said housing, aninfluencing coil mounted on said magnet between the poles thereof andprovided with an armature, a link connecting said armature operativelywith said diaphragm through the hole in the leg of said magnet, bindingposts supported from said strap, and leads from said coil to saidbinding posts.

7. The combination with a pair of spaced magnetic poles, of :2V spoolreceivable between said poles, and pole pieces detachably engageablcwith said spool and with respective poles, said spool and pole piecesbeing adapted to be introduced between said poles as a unit in slidingengagement therewith.

8. The combination with a pair of spaced pole members, of a spoolprovided in its ends with recesses, and tongues adapted to limit theapproach of upper and lower pole pieces in said recesses, together withpole pieces having inwardly extending spool engaging portions receivablein said recesses' and outwardly extending portions adapted to embracesaid pole members.

9. As a new article of manufacture, a pole piece having an approximatelyreotangular central portion, with o posite depending flanges on twosides, an upwardly extending flanges on the other two sides.

10. In a device of the character described the combination with amounting plate and a horseshoe magnet having one leg abutting saidmounting plate and connected therewith, of an influencing coil betweenthe diaphragm 6 'ing therefromthrough the ends thereof at substantiallythe level of said tongues, and pole pieces provided with flangesembracing the ends of said spool and spaced from the flan'gesof eachother by said tongues at 10 either side of said armature 11. In a deviceof the character described,

the combination with a mounting plate and a horseshoe magnet havingoneleg abutting said .mounting plate and connected there- 15 with, of aninfluencing coil between the poles (provided with upper and of saidmagnet a spool for said coil having its ends rovided with 'upper andlower recesses an intermediate tongues, an armature mounted in saidspool and projecting therefrom through the ends thereof at substantiallythe level of 'said tongues, and pole pieces provided with flangesembracing the ends of saidspool and spaced from the flanges of eachother by said tongues at either side of said armature, each of said polepieces having another pair-of flanges at right angles to the first andembracing the poles of said magnet.

I HUGO HELLER.

. JOHN C. MITCHELL.

